(i) Field of the Invention
The present invention relates to a therapeutic composition comprising at least one antigen, in particular an antigen of viral, bacterial or parasitic origin, or at least one in vivo generator of a compound comprising an amino acid sequence, and at least one adjuvant.
(ii) Description of Related Art
The use of adjuvants in therapeutic compositions of the vaccine type has been known for a long time. The main objective of these adjuvants is to allow an increase in the immune response. These adjuvants are diverse in nature. They may, for example, consist of liposomes, oily phases, for example the Freund type of adjuvants, generally used in the form of an emulsion with an aqueous phase, or, more commonly, may consist of water-insoluble inorganic salts. These inorganic salts may consist, for example, of aluminum hydroxide, cerium nitrate, zinc sulfate, colloidal iron hydroxide, calcium phosphate or calcium chloride. Aluminum hydroxide (Al(OH).sub.3) is the most commonly used adjuvant. These adjuvants are described in particular in the article by Rajesh K. Gupta et al "Adjuvants, Balance Between Toxicity and Adjuvanticity", Vaccine, Vol. 11, issue 3, 1993, pages 993-1306.
The adjuvants mentioned above have the drawback of limited efficiency. Moreover, they may induce a certain toxicity with regard to individuals treated. More particularly, when these therapeutic compositions are injected, the formation of lesions and other local reactions such as granuloma are observed at the point of injection. These drawbacks are less pronounced when the adjuvant is aluminum hydroxide. Accordingly, the latter compound is one of the most commonly used adjuvants. Recently, however, aluminum hydroxide, like all aluminum-based compounds, has come to be suspected of being a factor promoting the appearance of certain diseases, such as renal dysfunctions or Alzheimer's disease. In addition, it is known that aluminum hydroxide efficiently induces only humoral immunity and not cell immunity.